Color reproduction process



July 7, 1936. .A. e. HAPKE i 2,046,326.

' COLOR REPRODUCTION PROCESS Eiled'March B, 1935 BLUE COLOR I BED COLOR YELLOW COLOR.

Patented July 7, 1 36 UNITED STATES PATENT OFFICE 2,040,320 boron nrirnonucrros moosss Alwin G. Hapke, Chicago, 111. Application March a, 1935, Serial No. 10,072

'1 Claims. (61. 95--5.1)

This invention relates to instrumentalities and. processes for use in connection with color printing, or color reproduction, and to the method of printing in colors by running the paper or other 5 material through the printing press one or more times, such, for example, as three times for a thzeee color printing Job, of the well known charac r. I

Generally stated, the object of the invention is to provide certain novel steps in a color printing process or method of color reproduction of this character, for the purpose of reducing the cost of color printing, more particularly work of this kind in which two or more colors are 5 employed, in the production of colored pictures,

or ornamental work, thereby to not only reduce the cost of production, but also to insure, in some ways, more satisfactory and-effective results than heretofore. go It is also an object to provide certain details and features tending to increase the general emciency and the desirability of a color printing processor method of this particular charac er. 55 To the foregoing and other useful ends, the invention consists in matters hereinafter set forth and claimed and shown in the accompanying drawing, in which- Fig. 1 shows a positive print from the negative of the picture which it is desired to reproduce by color printing, with certain alterations therein made by hand, with respect to one of the colors to be used. in printing.

, Fig. 2 is a similar view showing another iden- 55 tical positive print altered by hand with respect to one of the other colors to be used in the printing of the desired picture.

Fig. 3 is a similar view showing another iden-' tical positive print. altered by hand with respect to to the third color of the three. color printing process by which the desired picture is to .be'

i reproduced.

Fig. 4 shows the print I with everything washed ofl except the portions that were treated 45 by hand in Fig. 1.

Fig. 5 is a similar view of what is shown in Fig. 2, with everything washed 0! except the lpgrtciions that were touched up or altered by to Fig. 6 is a similar view bearing a similar rela-" tion to Fig. 3 of the drawing.

Fig. 7 is a photographic negative of what is shown in Fig,- 4.

. Fig. 9 is a similar negative of what is shown in Fig. 6 of the drawing.

As thus illustrated, referring to Figs. 1, 2, and 3, it .will be understood that these are positive prints made from a photographic negative, each- 5 the same as the others, initially, uponthe completion of each print. These prints are made on plates, of any suitable character, as hereinafter more fully appears, which plates have been sensitized in a manner that will hereinafter more 10 fully appear. In Fig. 1'. the portions that are desired to be blue in the ultimate picture have been blacked or darkened by hand by a brush or other instrument. In Fig. 2, those portions which are desired to be in red in the ultimate picture have been similarly treated with a brush or other instrument. In Fig. 3, the portions of the ultimate picture that are; desired to'be in yellow have been blacked or darkened by a brush or other instrument.

Fig. 4 shows the plate shown in Fig. 1, but with everything washed oil! except the portions thatwere altered or treated by hand, leaving nothing but these portions on a white back- I ground. Fig. 5 is the plate shown in Fig. 2, similarly treated, leaving only the portions that were altered or treated by hand on a white baokground. Fig. 6 bears the same relation to Fig. 3, showing the plate washed up to remove everythingexcept the portions that are shown darkened by hand in Fig. 3 of the drawing.

The next step is to photograph, through a screen, each of a standard angle for its separate color, each of the three plates shown in Figs.

4, 5, and 6 of the drawing. Fig.- '7, therefore, I shows a photographic negative of the plate shown in Fig. 4 of the drawing. Fig. 8 similarly shows a photographic negative of the plate shown in Fig. 5 of the drawing. Similarly, Fig. 9 shows a photographic negative of the plate 40 shown in Fig. 8 of the drawing.

From here on, the process or method is substantially the same as that employed in three color printing work, which is as follows: 'The negative shown in Fig. '7 will be used .to produce a print on a zinc etching block, or other similar t block for printing, and everything will be etched away except what is shown in white in Fig. 7 of the drawing. A similar printing block will be made from'the negative shown in Fig. 8 of the drawing, and a third one from the negative shown in Fig. 9 of the drawing- The block made from the negative shown in Fig. '7' will be used to apply the blue colorto the picture; the plate I made from the negative shown in Fig. 8 will be of the stems .of the fleweralas shown in the drawing. In Fig. 4, for'eigample, the vase has been blacked or shaded, as weu as the leaves and of the picture is then some of the stems of the flowers, thus providing for the ultimate blue of the wise, and the ultimate green of the leaves and some of the flower stems, when the yellow color provided by the treatment shown in Fig. 6 'is applied over the leaves and some of the flower stems, but not over the ,vase shown in the drawing. Obviously, as indicated in Fig. 6, one of the flowers will be shown yellow, while, as indicated in Fig. 8, one of the flowers will be dark red, while the smaller flower will be a lighter shade of red,- or even a light pink. Obviously, some of the flo'viefrsj leaving merely the outline thereof, can be white,

or substantially so, as may be desired.

It will be understood, of course, that after the three printing blocks have done their work, and produced the picture in the.desired colors, the dark or other background can then be applied by another suitably made printing block, as

well as any black lining or other shading on top of the colors, sary for portions of the picture is put on last, ,after the different colors have been applied, leaving the vase and the flowers and leaves of the picture shown with a ground, as may be desired, in the well known manner.

In this way, by making inexpensive prints from the original negative, on as many metal plates as there are colors to be applied to the picture, aconsiderable reduction in the cost of production is obtained, as these prints on metal plates are then treated by hand, by blacking or darkening-the parts that are'to be colored, with one color or another, and the remainder washed off, leaving only those portions which have been darkened or treated by hand, whereby the process is simple as compare-- are employed,

and comparatively inexpensive, tively simple and cheap materials as well as only a minimum of manual labor and hand work. The three prints on metal plates are, in fact, blue prints, made from the one photographic negative, which latter is merely an utline affair, with lines for shading, such as would produce a print on ordinary blue print paper.

But the method of treating the three metal plates, to obtain practically blue print impressions thereon, is preferablyas follows:

The plates shown and described may'be stainless metal plates of one kind or another, but

preferably they are metal plates covered with white enamel, as the white enamel has a definite and well understood photographic value. The plates may be made of any inflexible and waterproof material having a hard white surface. These plates are sensitized with a solution comprising the regularblue print formula, but with the addition of albumin and gelatin, thereby forming an emulsion, the albumin for holding the blue print on the surface of the enamel, and the gelatin for binding all together and ha denwhereby all the black necesblack or colored backuse of the color scale, the gray paint, from ing by means ofthealum in the development bath. For the development of the exposed plates, they are placed in hot water and flxed ina bath of potassium bichromate and alum in the following proportions: one ounce of potassium 5 bichvomate, one ounce of alum, and twenty ounces of water. The plates are dried, and the color equivalent is applied to each in the various shades of gray, as indicated in the drawing. and as previously described, which shades are well ,known. Each of these shades has a specific dot formation when photographed through a screen. The color tone of each of these dot formations is known, and may be registered on a scale made for that purpose. Of course, very 16 obviously, with this method, it is easy to reproduce every color combination in the spectrum. The color scale, every shade of gray as applied to one color, is combined with every shade of gray as applied to each of the other colors, including 20 black, each of two othercolors, and each of screen negative is made thereof. The sensitizing 30 4 solution on the plates turns a blue color, the photographic value of 'which is known and can be utilized in the color processj Such blue areas, when not used for color value, can be removed with a damp cloth, .as previously explained, leaving these portions of the plate white. The use of metal or ceramic plates insures against stretching or shrinkage, as the final negatives must be in perfect register. By the 40 practically white to black, every color can be reproduced exactly, so that anyone unaccustomed to the use of color can match the shade. Also, it is important to observe that the solution employed for sensitizing the metal plate results, when the plate is developed, in an almost non-photographic shade of blue.

or course. while the method shown and described is useful in connection with color printing, it will be easily understood that the method can be used in a number of different ways to produce color reproduction, in the graphic arts.

Thus the final negatives are made by directly photographing the prints, after the latter have beentreatedwithabrush,inthemannerex-. plained, and each ori inal print is made from the original negative on a smooth white waterproof surface which has been sensitmed to produce a blue print positive on said surface. as

the direct result of the exposure of said surface so.

to light through the, ori inal negative. Each original print, as originally made, directly from the original negative, is visible to the naked eye, very plainly, when the print is developed, and

does notneed anything more thereafter, except manner print positive which is practically of non-photographic value, blacking or shading the portions of the print that are desired to appear in a certain color on the ultimate picture, washing off or removing all other portions of the print, leaving only the treated portions thereof on a white background, and producing a photographic negative of the print thus treated, by directly photographing said print, from which negative the zinc etching or other printing block, for this particular color, is then made.

2. A process as specified in claim 1, comprising the use of a plurality of prints of the character specified, with a different treatmentior each print, whereby the ultimate photographic negative of each print will be for a difierent color.

3. A process as specified in claim 1, com prising a plurality of prints from said original negative, with each print treated to represent a different color, whereby there are'then three ultimate negatives, each for use in making a diiferent printing block with one print treated to produce a block for blue, anotherfor red, and

another ior yellow, whereby the ultimate picture may include blue and yellow and green, as well as dark and light shades of red.

4. A process as specifled'in claim 1, said print being made on a smooth metal plate, said plate having white enamel thereon, to provide said white surface upon which the print is made.

5. A process as specified in claim 1, said print being made on a white sensitized blue print surface, directly from said negative, so that the resulting print is immediately an almost non-photographic shade of blue.

6. A process as specified in claim 1, said chromate and alum and water in the following sensitized surface being made by using an ennui-- proportions, to-wit: one ounce of potassium bi- 20 chroinate, one ounce o1 alum, and twenty ounces of water. 

